The present invention relates to magnetic disk drives such as hard disk drives.
In recent years, there has been a need to reduce the power consumption of electronics devices in many applications. This requires reducing the power consumption of magnetic disk drives, such as hard disk drives, used within these electronics devices. For example, to increase the operating time of a notebook computer, it is necessary to reduce the power consumption of its built-in hard disk drive.
On the other hand, there has been also a need to increase the capacity and the speed of hard disk drives, and therefore the data read/write rates have been increased over the years. This has led to an increase in the power consumption of circuits related to data read or write, such as the analog block of the channel and the serial ATA low-voltage block, preventing the power consumption of the hard disk drive from being reduced.
To address this problem, the operating voltage of the circuits has been reduced to, for example, 1.5 V, thereby reducing the power consumption. However, since the main unit of the electronics device (that is, the host side) usually supplies only 5 V of power to the hard disk drive, conventionally the following circuits are added to generate a power supply voltage of 1.5 V. A first linear regulator is provided within the analog IC to transform the 5 V power supply voltage to generate a 3.3-V voltage signal. Furthermore, the channel IC includes a second linear regulator. With this arrangement, the channel IC receives the 3.3-V voltage signal produced by the first linear regulator and changes it to a 1.5-V power supply voltage by use of the second linear regulator.